Need 'special' PSU...

[WilliamD]

I am building a laser table. I have the information I need and materials to build the basic powersupply, rectify it and run it through capacitors. The part I need, is to be able to have mach send the signals to adjust the power level of the supply. I know it has something to do with PWM. I need to be able to turn down the power between rapids. I know PWM has to do with switching, but I need some more information. Actually, I've found tons of info, but I need help understanding some of it. I really want to get some ideas going, and I will share mine.

- I've even gone as far as using a triac for the AC, and then hook a stepper up to it and drive it like a rotary axis. Simply turning up and down the voltage where needed.

I am still gathering info on how fast the laser power responds to a drop in voltage. I really need to work this out, as it's the last step. Any help or ideas would be appreciated! I virtually can't sleep until I figure this out!

[kreutz]

What you need is very simple if it is only turning on-off the power. All depends on the power consumption of your laser power supply (not the laser power output)

If you need to adjust power level it is a complete different story, it depends on the adjustment capability of the laser power controller, What kind of laser is it, pulsed?

Please, tell us what is the input voltage and power for that device as well as type of laser, power control type, in other words, we need a lot more information.

[WilliamD]

I will have to do some research to find out if it's pulsed or not. I don't think that I can just turn it off and on, that would be easy enough. So I would need to be able to vary the voltage. It will operate off of 120V AC, but it could probably be around 90V ac with what I'm going to be using it for at first. I really just need to get the project off the ground.

[WilliamD]

The power supply is going to be 20Kv at about 30 mA. I'm thinking to keep it simple enough, I'll just vary the AC input and not deal with the high voltage stuff. I'm using a group of 2Kv caps as my bank.

[kreutz]

Just a transformer, rectifier and High Voltage capacitors type power supply? What is your line voltage? Just by the numbers you gave me you have 600 Watt at the load, assuming 80% efficiency for the transformer and 0.7- 0.8 Power factor you need about 1 kva input power.

In order to test your idea ( Don't do this if you are using a switching power supply) try to get a 1 Kva variac (variable output voltage transformer 0-120% of your line voltage) and do some tests (use maximum 100%) until you know the voltage range for useful work of your laser. I assume it is a continuous wave laser since you didn't say anything about pulse-width and pulse frequency control.

After you know what voltage range you need let us know.

Disclaimer: High Voltage and Laser are two potentially lethal hazards by themselves, use protection equipment and special protection clothes, all tests should be done at a safe distance and if possible use a rigid polycarbonate shield between you and the equipment. Use laser approved goggles, etc, etc.....